Systems and methods for enhanced heat transfer loops

Abstract

The present application pertains to processes and systems for enhanced heat transfer. In some embodiments a process is described for removing a portion of a chemical from a heat transfer loop comprising a heat transfer fluid. The process may comprise adding a solvent to the heat transfer fluid in the heat transfer loop; removing at least a portion of the heat transfer fluid from the heat transfer loop; separating said removed heat transfer fluid into a permeate and a retentate using a membrane; and adding at least a portion of the permeate to the heat transfer fluid in the heat transfer loop.

What is claimed is: 
     
       1. A process for removing a portion of a chemical from a heat transfer loop comprising a heat transfer fluid wherein the process comprises:
 adding a solvent to the heat transfer fluid in the heat transfer loop; 
 removing at least a portion of the heat transfer fluid from the heat transfer loop; 
 separating said removed heat transfer fluid into a permeate and a retentate using a membrane; and 
 adding at least a portion of the permeate to the heat transfer fluid in the heat transfer loop wherein the process further comprises: 
 heating at least a portion of the retentate to a temperature at or above its liquid-liquid phase transition temperature range to form a multi-liquid phase solution comprising a first liquid phase and a second liquid phase; 
 separating the first liquid phase from the second liquid phase; and 
 adding at least a portion of the first liquid phase to the heat transfer loop; 
 wherein the first liquid phase comprises solvent and the second liquid phase comprises the chemical; and 
 cooling the removed heat transfer fluid to a temperature below an LCST cloud point temperature or heating the removed heat transfer fluid to a temperature above an UCST cloud point temperature to form a substantially single liquid phase before separating with the membrane; wherein the solvent comprises water and wherein the chemical comprises a glycol polymer, or a polypropylene glycol (PPG), or a polyethylene glycol (PEG), or a block-polymer, or a EO polymer, or a PO polymer, or a glycol ether, or a glycol ether polymer, or any combination thereof. 
 
     
     
       2. The process of  claim 1  wherein the retentate comprises a solution of chemical and solvent. 
     
     
       3. The process of  claim 1  wherein separating the first liquid phase from the second liquid phase comprises:
 allowing the first liquid phase and the second liquid phase to settle into a first liquid layer and a second liquid layer in a tank; 
 separating the first liquid layer from the second liquid layer. 
 
     
     
       4. The process of  claim 1  further comprising purifying the first liquid phase comprising solvent by removing at least a portion of the chemical using a membrane. 
     
     
       5. The process of  claim 1  further comprising:
 forming a second permeate and a second retentate from the first liquid phase using a membrane;
 wherein the second retentate comprises the chemical; 
 wherein the second permeate comprises the solvent; and 
 
 adding the second permeate to the heat transfer loop. 
 
     
     
       6. The process of  claim 5  further comprising cooling the first liquid phase to a temperature below the cloud point temperature of the second retentate before using the membrane. 
     
     
       7. The process of  claim 1  wherein the permeate comprises the solvent. 
     
     
       8. The process of  claim 1  further comprising cooling the heat transfer fluid to below its cloud point temperature before using the membrane. 
     
     
       9. The process of  claim 1  wherein the chemical comprises a polypropylene glycol. 
     
     
       10. The process of  claim 1  wherein the membrane comprises a membrane suitable for reverse osmosis, nanofiltration, organic solvent nanofiltration, or ultrafiltration, microfiltration, forward osmosis, osmotically assisted reverse osmosis, or osmotically assisted nanofiltration. 
     
     
       11. The process of  claim 1  further comprising monitoring the concentration of the chemical in the heat transfer loop. 
     
     
       12. The process of  claim 1  further comprising ceasing the adding of the solvent and the removing of the heat transfer fluid when the concentration of the chemical in the heat transfer loop is at or below a desired concentration. 
     
     
       13. The process of  claim 1  wherein the volume of the solvent added is about the same as the volume of chemical removed. 
     
     
       14. The process of  claim 1  which further comprises controlling the volume of heat transfer fluid. 
     
     
       15. A process for adding a portion of a chemical to a heat transfer loop comprising a heat transfer fluid wherein the process comprises:
 adding the chemical to the heat transfer fluid in the heat transfer loop; 
 removing at least a portion of the heat transfer fluid from the heat transfer loop; 
 separating said removed heat transfer fluid into a permeate and a retentate using a membrane; and 
 adding at least a portion of the retentate to the heat transfer fluid in the heat transfer loop wherein the process further comprises cooling the removed heat transfer fluid to a temperature below an LCST cloud point temperature or heating the removed heat transfer fluid above an UCST cloud point temperature to form a substantially single liquid phase before separating with the membrane wherein the chemical comprises a glycol polymer, or a polypropylene glycol (PPG), or a polyethylene glycol (PEG), or a block-polymer, or a EO polymer, or a PO polymer, or a glycol ether, or a glycol ether polymer, or any combination thereof. 
 
     
     
       16. The process of  claim 15  wherein the retentate comprises the chemical. 
     
     
       17. The process of  claim 15  wherein the permeate comprises a solvent. 
     
     
       18. The process of  claim 15  which further comprises controlling the concentration of the chemical in the heat transfer loop. 
     
     
       19. The process of  claim 15  wherein the volume of the chemical added is about the same as the volume of solvent removed. 
     
     
       20. The process of  claim 15  which further comprises controlling the volume heat transfer fluid. 
     
     
       21. A process for replacing a first chemical with a second chemical in a heat transfer loop comprising a heat transfer fluid comprising the first chemical wherein the process comprises:
 adding the second chemical to the heat transfer fluid in a heat transfer loop; 
 removing at least a portion of the heat transfer fluid from the heat transfer loop; 
 separating said removed heat transfer fluid into a permeate and a retentate using a membrane; and 
 adding the retentate to the heat transfer fluid in the heat transfer loop wherein the first chemical or the second chemical comprises a glycol polymer, or a polypropylene glycol (PPG), or a polyethylene glycol (PEG), or a block-polymer, or a EO polymer, or a PO polymer, or a glycol ether, or a glycol ether polymer, or any combination thereof. 
 
     
     
       22. The process of  claim 21  wherein the permeate comprises the first chemical and the retentate comprises the second chemical. 
     
     
       23. The process of  claim 21  wherein the membrane comprises a nanofiltration membrane comprising a pore size to allow substantial permeation of the first chemical and substantial rejection of the second chemical. 
     
     
       24. The process of  claim 21  further comprising:
 heating the permeate to a temperature at or above its liquid-liquid phase transition temperature range to form a multi-liquid phase solution comprising a first liquid phase and a second liquid phase; and 
 separating the first liquid phase from the second liquid phase; 
 wherein the first liquid phase comprises solvent and the second liquid phase comprises first chemical. 
 
     
     
       25. The process of  claim 21  wherein the liquid-liquid phase transition temperature range of a composition comprising the first chemical and the solvent is different than the liquid-liquid phase transition temperature range of a composition comprising the second chemical and the solvent. 
     
     
       26. A process for replacing a second chemical with a first chemical in a heat transfer loop comprising heat transfer fluid wherein the process comprises:
 adding a first chemical to the heat transfer fluid in a heat transfer loop; 
 removing at least a portion of the heat transfer fluid from the heat transfer loop; 
 separating said removed heat transfer fluid into a permeate and a retentate using a membrane; and 
 adding the permeate to the heat transfer fluid in the heat transfer loop wherein the first chemical comprises a glycol polymer, or a polypropylene glycol (PPG), or a polyethylene glycol (PEG), or a block-polymer, or a EO polymer, or a PO polymer, or a glycol ether, or a glycol ether polymer, or any combination thereof. 
 
     
     
       27. The process of  claim 26  further comprising:
 heating the retentate to a temperature at or above its liquid-liquid phase transition temperature range to form a multi-liquid phase solution comprising a first liquid phase and a second liquid phase; and 
 separating the first liquid phase from the second liquid phase; 
 wherein the first liquid phase comprises the solvent and the second liquid phase comprises the second chemical.